SmartHand: Merging Mind and Machine

"Luke" Arm. Photo credit: popsci.com

Frederick Downs, Jr., a Vietnam veteran and director of VA’s Prosthetic and Sensory Aids Service who lost his left arm, was "brought to tears" when a prosthetic arm allowed him to take a drink of bottled water with a single motion.

Designed by Segway inventor Dean Kamen, the “Luke” prosthetic arm is named after Luke Skywalker’s famous duel with Darth Vader in Star Wars Episode V – The Empire Strikes Back (“… I am your father,” reveals Vader after cutting off Luke’s dueling hand with his lightsaber).

Prof. Yosi Shacham-Diamand of TAU’s Department of Engineering, working with a team of European Union (EU) scientists, has now gone a step further than Kamen. His team has successfully wired a state-of-the-art artificial hand to existing nerve endings in the stump of a severed arm. Here’s a video (courtesy of the BBC News):

Dubbed SmartHand, “the smart bio-adaptive hand prosthesis,” this intelligent artificial prosthetic hand mimics the movement of a real human hand and gives the wearer a true sensation of feeling and touch. Four electric motors and 40 sensors are directly linked to the brain and activated when a SmartHand touches an object. "I am using muscles which I haven’t used for years. I grab something hard, and then I can feel it in the fingertips, which is strange, as I don’t have them anymore. It’s amazing," says Robin af Ekenstam of Sweden, the project’s first human wearer.

I grab something hard, and then I can feel it in the fingertips, which is strange, as I don’t have them anymore.

SmartHand is a highly innovative, interdisciplinary project, combining forefront research from material sciences, bio and information technologies with cognitive neuroscience. Drawing on the earlier work of The Artificial Hand Project (biocompatibility, recognition of bio-signals), Cyberhand (biomechatronics), and FreeHand (nerve recordings and stimulations), SmartHand  is very much like the prosthetic hand that Luke Skywalker receives after his rescue from Cloud City — except lacking skin. While the prototype looks somewhat “robotic” now, SmartHand researchers plan to equip it with artificial skin in the future that will give the wearer’s brain even more tactile feedback. "Perfectly good nerve endings remain at the stem of a severed limb," says Dr. Shacham-Diamand. "Our team is building the interface between the device and the nerves in the arm, connecting cognitive neuroscience with state-of-the-art information technologies."

While the “Luke” prosthetic arm currently requires a foot controller, the SmartHand is controlled quite naturally by the wearer’s thoughts. “The muscle signals, also called ElectroMyoGraphic (EMG) signals, are recorded by surface electrodes applied on the skin so that information can be transmitted to the motor in the artificial hand,” reports the project’s FAQ. “So, if the amputee thinks of extending the fingers, EMG signals from extensor muscles make the motor extend the fingers in the hand prosthesis. If the amputee thinks of closing the hand, corresponding signals from flexor muscles instruct the motor to close the artificial hand.”

SmartHand. Photo credit: elmat.lth.seThere are just a few types of hand prostheses available on the market today, most of them allowing very simple movements — basically opening and closing the hand using EMG signals. They are heavy and difficult to keep clean and require power support from heavy batteries. Also, the wearer has no feeling. With SmartHand, amputees can accomplish more complex movements with a hand that is easily cleaned.  More importantly, wearers can feel what they touch and grasp.

The TAU/EU team could also have built bionic legs wired to the brain. The team first chose to build a hand, however, because of its complexity. "The fingers in the hand are the most complex appendages we have," says Prof. Shacham-Diamand. "The brain needs to synchronize the movement of each digit in a very complicated way."

Simple leg prosthetics are used today even among animals. Recently, Meadow-the-Calf became the first bovine calf fitted with double prosthetics, according to Colorado State veterinarian Dr. Robert Callan. Lucky the box turtle in Petaluma, California lost his front legs in what was believed to be an attack by a raccoon. Now he’s back sauntering around with furniture sliders taped to his belly.

The poster child amputee is fashion model Aimee Mullins, who lost both her legs to fibular hemimelia (missing fibula bones). With her 12 pairs of legs, she considers herself “super-enabled” rather than “disabled.” Here’s a video of her recent TED presentation:

Her stirring story is an inspiration to all amputees. With the prospect of yet another pair of legs based on the TAU/EU technology –- this time perhaps allowing her to feel prosthetic toes –- she’ll be able to use her mind to directly control her legs.

Merging mind and machine… tens of thousands of veterans and other amputees now have the same promise as Luke Skywalker — replacement limbs that respond to thought.

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